JPH04352536A - Route selecting system for speech path of atm exchange - Google Patents

Abstract

PURPOSE:To reduce the call damage rate of a high-speed call by providing a route decision processing part to select and decide the inside route of a speech path and a permission judgement processing part to judge whether the decided route can pass a user request call or not. CONSTITUTION:While referring to a built-in selection order information storage table, a route decision processing part 3 decides information expressing a route selection order to the plural routes toward the same output path of an ATM switch 1. The built-in selection processing part selects the route to allocate the call in a cramming system according to the order of the decided information. Concerning this selected route, a permission judgement processing part 2 judges whether the request call of a user can be passed or not, and the route of the switch 1 is controlled. In comparison with the selecting system of uniforming the loads of all the routes, the call damage rate of the high-speed call such as a moving image or the like is reduced by the system of allocating the route according to the decided order without considering the kind of the call to the plural routes.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call path routing system for an ATM switch which has a plurality of routes for the same outgoing route. ATM (Async) is the next generation switching system.
The CCITT (International Telegraph and Telephone Consultative Committee) has agreed on the broadband ISDN (Integrated Transfer Mode) switching technology.
Digital Services
Research has been actively conducted in each period as a technology to realize the work. On the other hand, in ATM communication, voice,
Since various kinds of traffic with different bearer speeds and burstiness of information such as data and video images are handled uniformly, if bursty traffic is mixed, the traffic added to the communication path will fluctuate greatly, causing cell discards and delays. There is a problem in which the quality of services deteriorates, and a solution to this problem is desired.

0002

[Prior Art] Conventional STM (Synchronous
Transfer Mode: Synchronous transfer mode) Switches use time division multiplexing to transfer one frame (125
The amount of data transmitted corresponds to the number of frames or the number of time slots used.

[0003] In the ATM switching system, data corresponding to various calls such as voice, images (still images, moving images), computer data, etc. are stored in a fixed length called a cell (a 5-byte header including a destination etc. and a 48-byte header including a 48-byte address). The data is structured into blocks (consisting of information fields), is multiplexed and transmitted within the communication path, and is sent out to the outgoing path by switching on a cell-by-cell basis.

[0004] In such an ATM switch, various types of traffic with different bearer speeds and burst characteristics are handled in a unified manner, so the traffic added to the communication path fluctuates greatly, causing cell discard (cell loss) and delays. The quality of service will deteriorate. For this reason, conventional exchanges (circuit exchanges that allocate transmission paths for each call) that have multiple routes for the same outgoing route have been proposed, and switches that distribute the traffic load have been proposed, but there are still multiple routes available. The method for selecting a route for a switch that has a route has not been considered.

[0005]

[Problem to be solved by the invention] The above-mentioned conventional STM
There are no exchanges that have internal switches that have multiple routes, and even ATM exchanges are not known to have multiple routes for the same outgoing route.

[0006] Since ATM exchanges handle a variety of calls, including 64 Kbps voice calls and 150 Mbps video communications, the call loss rate (probability of rejection due to lack of transmission bandwidth, etc.) due to differences in transfer speeds. is 150Mb
The range of ps becomes large. For this reason, it is necessary to prevent the call loss rate from increasing even when making high-speed calls.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a routing system for ATM exchanges that does not increase the call loss rate of high-speed calls when there are multiple routes on the same outgoing route within a switch.

[0008]

[Means for Solving the Problems] FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a diagram explaining the first principle of the present invention, FIG. 3 is a diagram explaining the second principle of the present invention, and FIG. 4 is a diagram explaining the second principle of the present invention. The third principle configuration diagram of
FIG. 5 is a fourth principle configuration diagram of the present invention.

In FIG. 1, 1 has a plurality of input highways and a plurality of output highways arranged in a matrix, and the switches at each stage are connected to the switches at the previous stage or the stage after the same output highway. An ATM switch 2 that has multiple routes for each route determines whether a user's requested call can pass through the route determined by the route determination unit by checking the amount of bandwidth actually used in each route and the bandwidth of that route. 3 is a route determination processing unit that selects an appropriate route from among a plurality of routes within the switch in response to a switch connection request from the call processing unit;
4 is a call processing unit that accepts call connection requests from users.

The ATM switch shown in FIG. 1 has a three-stage configuration, and the first stage switch is M×N (the number of inputs is M, the number of outputs is N,
(The same applies hereafter), the switches in the intermediate stage are K×N, and the switches in the final stage are L×P. Also, in Figures 2 to 5, 3a
3d is a route determination processing unit, 30 in FIG. 2 is a stuffed route selection processing unit, and 31 is a selection order information storage table that stores information representing route selection order for multiple routes to the same outgoing route, FIG. , 32 is a call type stuffed route selection processing unit, and 33 stores route information in which multiple routes to the same outgoing route are assigned to each call type and information representing the route selection order within each type. Represents a call type selection order information storage table.

Furthermore, in FIG. 4, 34 is a uniform load route selection processing unit, and 35 is an in-switch unit that maintains the logical usage band for calls that has already been assigned to each route of each output route of the ATM switch and set within the switch. Used bandwidth database (DB), 36 is a call type route allocation table storing route information allocated to each call type for multiple routes to the same outgoing route, and in FIG. 5, 34 to 36 are the same reference numerals as in FIG. 37 represents the route allocation table update unit.

[0012] In response to a call connection request, the present invention prepares various data for making judgments corresponding to each route selection method in the route determination section, and uses the data to determine a route according to each route selection method. It is something.

[0013]

[Operation] In FIG. 1, when a connection request call for which a user declares the bandwidth to be used is input to the call processing unit 4, the call processing unit 4 determines the outgoing route (outgoing switch number) corresponding to the destination of the call and the call processing unit 4. After identifying the on switch number, the route determination processing unit 3
The used bandwidth, incoming switch number, and outgoing switch number are supplied to the The route determination processing unit 3 uses information from the inbound highway to determine one route from among the same outbound routes. The determined route is used in the permission determination processing unit 2 to determine whether the requested call can pass, and if it is possible to pass, controls the ATM switch 1 to transfer the cells of the requested call through the determined route.

FIGS. 2 to 5 show the principle configuration diagram of the route determination processing section 3 that executes the route selection function in the configuration of FIG. 1.
Shown below. 2 to 5 show the first to fourth principle configurations of the present invention. In the first principle configuration shown in Figure 2,
Selection order information storage table 31 of route determination processing unit 3a
The selection order information assigned to each of a plurality of routes to the same exit route is stored in advance. In other words, multiple routes provided for a certain exit route are R1 to R.
When n is selected, the selection order is set such that R1 is number 1 and R2 is number 2.

The stuffed route selection processing section 30 selects a route for allocating calls requested by the call processing section 4 (FIG. 1) in accordance with the order stored in the selection order information storage table 31. In this case, the bandwidth of the route that is higher in order (
If the transmission capacity (transmission capacity) is not available due to a call already assigned to that route (when it is rejected by the permission judgment processing unit or it is identified that there is no bandwidth available by referring to the logical usage band database (not shown)), , is assigned to the root in the next order. In this way, new request calls are packed in order according to the selection order, so it is called a stuffed routing method.

In the second principle configuration shown in FIG. 3, a plurality of routes to the same outgoing route are assigned to each call type in advance in the call type selection order information storage table 33 of the route determination processing section 3b. Selection order information given to each type of route is stored. For example, in the case of type 1 among multiple routes R1 to Rn, as in the above example, R1,
Give the selection order in the order of R2, R3, etc. For type 2, set it as Rn, Rn-1, Rn-2, etc., and for type 3, set it as R3, R4, R5, etc. .

When the call type packed route selection processing unit 32 receives the requested call bandwidth etc. from the call processing unit 4 (FIG. 1) and identifies the type based on the declared bandwidth, burst rate, etc., the call type packed route selection processing unit 32 stores the call type selection order information storage table. From 33 onwards, the routes with the higher selection order among the routes assigned to the corresponding type are allocated in the same way as in the first principle configuration described above. This is called a call type stuffing selection processing method.

Next, in the third principle configuration shown in FIG. 4, information on routes allocated for each call type is stored in the call type route allocation table 36 of the route determination processing unit 3c, and information on routes allocated for each call type is further stored. The database 35 stores the bandwidth already allocated to the route of each switch. When the uniform load route selection processing unit 34 detects a plurality of routes assigned to the call type of the requested call using the call type route assignment table 36, the uniform load route selection processing unit 34 selects a switch from among these routes from the in-switch bandwidth usage database 35. Select the route with the least load. This method is called call type uniform load route selection method.

Next, in a fourth principle configuration shown in FIG. 5, the internal configuration of the route determination processing section 3d is such that a route allocation table updating section 37 is added to the route determination processing section 3c of FIG. The uniform load route selection processing unit 34 receives the result of the determination by the permission determination processing unit 2 (FIG. 1) of whether or not the route determined by the route determination processing unit 3d is passable, but this determination result is not an acceptable response. , the call type is used as a parameter to instruct the route allocation table updating unit 37 to update the call type route allocation table 36.

[0020] Upon receiving this instruction, the route allocation table update unit 37 is started and the in-switch bandwidth usage database 35 is updated.
The call type route allocation table 36 is updated based on the data, and route selection is dynamically changed. That is, when each route assigned to a certain call type is occupied (there is no free capacity), the route (switch) with the lowest usage rate among the routes assigned to other call types is found. The call type route allocation table 36 is updated so that the detected route is allocated to the route of the call type that cannot be accepted. This method is called a dynamic call type route selection method.

[0021]

[Example] FIG. 6 is a processing flow of an embodiment of stuffed route selection, FIG. 7 is a processing flow of an embodiment of call type stuffed route selection, and FIG. 8 is a selection order information storage table used in the processing of FIG. FIG. 9 is a diagram showing the contents of the call type selection order information storage table used in the process of FIG.

The processing flow shown in FIG. 6 is executed by the stuffed route selection processing unit 30 of the first principle configuration (based on the stuffed route selection processing method) of the present invention shown in FIG. Information storage table (31 in Figure 2)
) is shown in FIG. 8.

First, it is determined whether there is a connection order from the call processing unit 4 (FIG. 1) (S1 in FIG. 6), and if there is, a register having a selection order number as a variable is set to 0 (S2 in the same). Next, the selection order number is incremented by one (S3), the selection order information storage table 31 is accessed, and the second stage switch number indicated by the selection order number is extracted (S4).

The contents of the selection order information storage table shown in FIG. 8 are as follows: When the ATM switch 1 shown in FIG. 1 is provided with the configuration shown in FIG. The route is represented by the second-stage switch number, and the selection order of the multiple routes is stored.

[0025] Here, to explain the configuration example of the ATM switch shown in FIG.
, M intermediate stage (second stage) switches S21 to S2M, L output stage switches S31 to S3L,
A plurality of links L111 to L1KM connect the input stage switch and the second stage switch, and a plurality of links L211 to L2ML connect the second stage switch and the output stage switch.
is provided. With this configuration, for example, when connecting from the input stage switch S11 to the output highway of the output stage switch S3L, as an internal route within the ATM switch,
There are links to the second stage switches via links L111 to L11M. Thereafter, each second-stage switch is connected to the output highway of switch S3L by a route passing through links L21L to L2ML, respectively.

Therefore, in FIG. 8, in the ATM switch as described above, a plurality of routes (links connecting the input stage and the second stage switch) for connecting each input stage switch to a specific output route are shown as two. It is expressed by the stage switch number, and the selection order among them is shown.

Returning to FIG. 6, the permission determination processing unit 2 (see FIG. 1) (S5)
). Since the permission determination processing unit 2 (Fig. 1) knows the amount of ATM cell traffic actually transferred to each route, it determines whether the band requested by the user can be transmitted by the route notified from the route determination unit. If possible, please accept permission (O
K), if it is not possible, send a refusal to the route determining section. The processing of this permission determination processing section is realized by a conventional technique.

The permission determination processing section determines whether or not acceptance is OK (S6), and when OK is returned, it notifies call processing section 4 of acceptance OK (S7). Also,
If the acceptance is refused, the selection order information storage table (Figure 8
), and if it is the last route, the call processing unit is notified of rejection (S9).

In this way, in the packed route selection processing method, when a requested call occurs, the call is once assigned to multiple routes for the same outgoing route in a predetermined order, and then the result of the rejection decision in the permission decision processing section is Therefore, in the case of rejection, by assigning the route with the next rank, it is possible to pack the route into each route according to the rank.

FIG. 7 shows a processing flow executed by the call type stuffed route selection processing unit 32 of the first principle configuration of the present invention (based on the call type stuffed route selection method) shown in FIG. FIG. 9 shows an example of the contents stored in the call type selection order information storage table (33 in FIG. 3) used for the call type selection order information storage table (33 in FIG. 3).

First, to explain an example of the contents stored in the table shown in FIG. 9, call types are divided into 1 to N, and multiple routes (second-stage switch numbers) are assigned to each call type. In this case, the same route may be shared by multiple call types. As shown in FIG. 9, a selection order is set among a plurality of routes assigned to each call type. In addition,
Examples of call types include audio (64 Kbps), still images (30 Mbps), and moving images (150 Mbps).

To explain the processing flow in FIG. 7, it is determined whether there is a connection order (request) from the call processing unit (S1 in FIG. 7).
), if there is an order, the selection order number is set to "0" and the selection order number is incremented by one (S2, S3). Next, the call type selection order information storage table shown in FIG. 9 is accessed to extract the second stage switch number indicated by the requested call type selection order number (S4). This second-stage switch number corresponds to the second-stage switch in the ATM switch (see FIG. 1) described with reference to FIG. 6 above.

The extracted second-stage switch number, the incoming switch number to which the requested call is input, and information on the declared band of the requested call are notified to the permission determination processing unit 2 (FIG. 1) (S5). The subsequent processing is similar to steps S6 to S9 in the packing method processing flow shown in FIG. 6 above.

FIG. 10 is a processing flow of an embodiment of uniform load route selection. This processing flow is executed in the uniform load route selection processing section 34 of the third principle configuration of the present invention (based on the call type uniform load route selection method) shown in FIG. FIG. 11 is a diagram showing the contents of the call type route allocation table 36 used in this process, in which the second-stage switch number of the ATM switch (FIG. 1) as described above corresponds to each call type, and the allocated route information is It is stored as .

Although not shown in the in-switch bandwidth usage database (35 in FIG. 4) used in this call type-specific load uniform route selection method, the request information already assigned to each route by each request call is also stored in the switch bandwidth database (35 in FIG. 4). The result of adding the declared bandwidths of calls is stored, and by referring to this content, the amount of used bandwidth (sum of declared bandwidths) in the route connecting to each second-stage switch, that is, the usage rate can be found.

To explain FIG. 10, it is determined whether there is a connection order from the call processing unit (S1 in FIG. 10), and if there is a connection order, the call type route allocation table is accessed and the requested call type is determined. The route assigned to the route is extracted (S2). Next, the usage bandwidth amount of each extracted route is retrieved from the in-switch bandwidth usage database, and a route with a uniform load is selected (S3). Specifically, for example, the route with the lowest current load is selected and equalized. Next, the selected route information (second-stage switch number, incoming switch number input by the requesting call, and information on the declared band of the requesting call) is notified to the permission determination processing unit 2 (FIG. 1) (S4)
.

The permission determination processing unit 2 looks at the actual traffic volume on the notified route (which does not necessarily match the sum of the declared bandwidths) and determines whether the requested call bandwidth can be allocated to that route. The results are sent to the route determining section. This permission determination processing unit determines whether or not the acceptance is OK (S5), and if OK is returned, the acceptance is accepted.
K is notified to the call processing unit 4 (S6). Further, in the case of refusal of acceptance, the call processing unit is notified of the refusal of acceptance (S7).

FIG. 12 is a processing flow of an embodiment of updating the call type route allocation table. This processing flow is executed in the route allocation table updating unit 37 of the fourth principle configuration (dynamic call type route selection method) of the present invention shown in FIG. First, the uniform load route selection processing section 34 (
5), it is determined whether there is a request to update the call type route allocation table (S1 in FIG. 12), and if there is a request, the in-switch bandwidth usage database 35 (FIG. 5) is accessed, and the Im =ΣU2mi (i=1~L
) from m=1 to M, and find m with the least load (S2). However, the code Uij in this formula
k is the used band of link Lijk, and Im is,
It represents the load of the m-th row switch (represented by Sm) among the plurality of switches S21 to S2M provided as second-stage switches in the ATM switch configuration of FIG.

As a result, when the second stage switch (Sm) with the least load is extracted, the route to that Sm is added to the route allocation table for the rejected call types (S3). As a result, the number of routes assigned to the rejected call type can be increased, and requests for that call type can be accepted.

Next, if the call type is routed to the second-stage switch Sm whose call type has been changed as described above, and Sm is the only switch that can use that call type, then
Sm is left as is without being deleted from the call type table. If there are other switches other than Sm that can use the call type, the route passing through the switch of Sm from that call type is deleted (S4).

For example, if Sm is the only second-stage switch that can be used for voice calls, if that route becomes unavailable for voice calls, it will no longer be possible to accept voice calls at all, so it is left as is. Next, the operation of each of the above embodiments will be explained using a specific example.

FIG. 13 shows a specific example of the configuration of an ATM switch, in which the input stage switches are S11, S12, S13,
The second stage (middle stage) switches are S21, S22, and S23.
, the output stage switches are composed of S31, S32, and S33. Figure 14 shows the state of a call requesting connection, and there are two examples of call types: voice call (required speed 64 Kbps) and video call (required speed 150 Mbps), and the input stage switch number for each call is S11, and the output stage switch number is S33.

First, a specific example of route determination using the packed route selection method according to the first principle of the present invention (FIGS. 2 and 6) will be described. In this case, the information shown in Figure 15 is stored in the selection order information storage table (31 in Figure 2), and the logical usage bandwidth within the link (value added to the declared bandwidth of calls assigned to each link) is as shown in Figure 16. Assume that it looks like this. In addition, L111 in the link name column of Figure 16,
L112...L233 are respectively switches S11
Link connecting from switch S21 to switch S11
A link connecting from switch S22 to switch S22, ... represents a link connecting from switch S23 to switch S33,
The left half is the link that connects the input stage switch and the second stage switch, and the right half is the link that connects the second stage switch and the output stage switch.

At this time, for example, when a voice call as shown in FIG. 14 is requested, a route is selected through S21 of the second stage switch according to the selection order shown in FIG. (not used in the processing flow)
Even when referring to
Since there is enough room to add , number 1 (S21) is selected as the second stage switch.

On the other hand, if the moving image shown in FIG. 14 is requested at this time, the capacity of the link passing through the first switch as the second stage switch is 900+150=1050 Mbps, which exceeds the bandwidth capacity of the link, so the next The second priority (S22) is selected, and since there is a margin in the link L112 (150 Mbps according to FIG. 16), this is selected.

Next, the second principle of the present invention (FIGS. 3 and 7)
), a specific example of route determination using the call type packed route selection method will be explained. In this case, it is assumed that the contents of the call type selection order information storage table are as shown in FIG. 17, and the contents of the logical usage band database within the link are as shown in FIG. 18. Here, when a voice call is requested, the route with the first selection order (second stage switch number) when the call type in FIG. 17 is voice is S21,
Since there is also a margin in the corresponding link (L111) shown in FIG. 18, the second stage switch No. 1 (S21) is selected. In the case of a moving image, the selection order of moving images 1 to 2 in Figure 17 is selected.
The route of the third stage switch (S23) and the second stage switch (S22) of the selection order 2 (L113, L11
2) is not selected because it is busy, and second-stage switch No. 1 (S21) is selected in the same way as for the voice call.

Next, the third principle of the present invention (FIGS. 4 and 10)
), a specific example of route determination using the call type load uniform route selection method will be explained. In this case, it is assumed that the call type route allocation table stores contents as shown in FIG. 19, and the in-switch logical bandwidth usage database stores contents as shown in FIG. 20.

According to the table of FIG. 19, for a voice call request, there is only one route that passes through the second stage switch No. 1, so this switch (S21) is selected. In the case of a moving image, according to the table in FIG. 19, No. 2 (S22) and No. 3 (S23) are selected as the second stage switches, but each link usage band (L) stored in FIG.
113, L112), the usage band of No. 3 (S23) is smaller, so No. 3 is selected in order to equalize the load.

Next, the fourth principle of the present invention (FIGS. 5 and 12)
) A specific example of the route allocation table updating method in the call type load uniform route selection method will be described. In this example, the call type route assignment table is the same as in the example above.
It is assumed that the content is similar to 9. It is also assumed that the in-switch logical bandwidth usage database has the contents shown in FIG. In this state, if an order to refuse acceptance comes from the uniform load route selection processing unit (34 in FIG. 5) of the route determination unit to the route assignment table update device, the route assignment table update device switches the switch shown in FIG. The call type route allocation table shown in FIG. 19 is updated as shown in FIG. 22 based on the data in the internal usage band database. In other words, for a call whose call type is a moving image, the input switch S
Figure 19 shows the route from No. 11 to the second switch.
As shown in Figure 21, only switches 2 (S22) and 3 (S23) on the second stage were allocated, but as shown in Figure 21, the two links are at the limit of their bandwidth capacity, so new video images cannot be created. call cannot be transmitted. Therefore, when searching for a link with a low usage rate (the link connecting switch S11 to the second-stage switch) using FIG. 21, link L11
1 is detected (a route that passes through switch No. 1), this second-stage switch number S21 is newly assigned to the video call type, and only this switch is assigned to the voice call type. Therefore, it can still be assigned to the voice call type as is.

[0050]

[Effects of the Invention] According to the selection method based on the first principle of the present invention, routes are assigned to multiple routes in a predetermined order without considering the call type, so the load on all routes is made uniform. Compared to such route selection methods, the call loss rate for high-speed calls such as video calls can be kept low. Also,
According to the selection method based on the second principle, by determining the order in which routes are allocated for each type of call, it can be expected that the statistical multiplexing effect of calls of the same type can be increased. Also,
The call loss rate for high-speed calls can also be kept low as in the first selection method described above.

Furthermore, according to the selection method based on the third principle of the present invention, in order to equalize the load of the same call type within the switch based on the usage band information of each call type, acceptance of the result of permission determination processing is rejected. The probability of this happening can be reduced. Furthermore, by updating the call type route allocation table based on the bandwidth usage information in the switch that changes from time to time according to the fourth principle of the present invention, the call loss rate of high-speed calls can be reduced in the invention according to the third principle of the present invention. It can be suppressed.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a first principle configuration diagram of the present invention.

FIG. 3 is a second principle configuration diagram of the present invention.

FIG. 4 is a third principle configuration diagram of the present invention.

FIG. 5 is a fourth principle configuration diagram of the present invention.

FIG. 6 is a process flow of an embodiment of stuffed route selection.

FIG. 7 is a process flow of an embodiment of call type stuffed route selection.

FIG. 8 is a diagram showing the contents of a selection order information storage table used in the process of FIG. 6;

9 is a diagram showing the contents of a call type selection order information storage table used in the process of FIG. 7; FIG.

FIG. 10 is a processing flow of an embodiment of uniform load route selection.

FIG. 11 is a diagram showing the contents of a call type route allocation table.

FIG. 12 is a processing flow of an example of updating a call type route allocation table.

FIG. 13 is a diagram showing a specific example of the configuration of an ATM switch.

FIG. 14 is a diagram showing the state of a call requesting connection.

FIG. 15 is a diagram showing contents stored in a selection order information storage table.

FIG. 16 is a diagram showing the contents of an intra-link logical bandwidth usage database.

FIG. 17 is a diagram showing the contents of a call type selection order information storage table.

FIG. 18 is a diagram showing the contents of an intra-link logical bandwidth usage database.

FIG. 19 is a diagram showing the contents of a call type route allocation table.

FIG. 20 is a diagram showing the contents of an in-switch logical bandwidth usage database.

FIG. 21 is a diagram showing the contents of an internal switch logical bandwidth database used for updating the call type route allocation table.

FIG. 22 is a diagram showing the contents after the call type route allocation table is changed.

[Explanation of symbols] 1 ATM switch 2 Permission determination processing unit 3 Route determination processing section 4 Call processing section

Claims (4)

[Claims] Claim 1: In a route selection method for a call route in an ATM switch that has multiple routes for the same outgoing route, a route determination processing unit that selects and determines an internal route for the call route, and a route determination processing unit that selects and determines an internal route for the call route, and a a permission determination processing unit that determines whether the requested call can pass, and the route determination processing unit includes a selection order information storage table that stores information representing a route selection order for a plurality of routes to the same outgoing route; , and a selection processing unit that selects a route for allocating calls in a packed manner according to the order of the selection order storage table. [Claim 2] In a route selection method for a call path in an ATM switch that has multiple routes for the same outgoing route, a route determination processing section that selects and determines an internal route for the call path, and a route determination processing unit that selects and determines an internal route for the call path, and a a permission determination processing unit that determines whether a requested call can pass through; a call type selection order information storage table that stores information representing the selection order, and a route that extracts a route corresponding to the requested call type from the call type selection order information storage table according to the selection order information and allocates calls in a packed manner. and a call type stuffed route selection processing unit that selects the
A method for selecting routes for calls in TM exchanges. 3. In a route selection method for a call path in an ATM switch that has multiple routes for the same outgoing route, a route determination processing unit that selects and determines an internal route for the call path, and a route determination processing unit that selects and determines an internal route for the call path, and a a permission determination processing unit that determines whether a requested call can pass through; An allocation table, an in-switch bandwidth usage database that holds the logical usage bandwidth of calls already assigned to each outgoing route of the ATM switch and set within the switch, and a requested call bandwidth database from the call type route assignment table. The route information assigned to the type is retrieved, the numerical value of the logical bandwidth usage of each route held in the in-switch bandwidth usage database is determined, and the method is selected that makes the load on each route uniform by allocating requested calls. 1. A method for selecting a route for a call path in an ATM switch, comprising: a uniform load route selection processing section. 4. In claim 3, the route determination processing section includes a table updating section that updates the call type route allocation table, and the table updating section receives an instruction to change the table from the uniform load route selection processing section. and updates the route assignment stored in the call type route assignment table using the data of the in-switch bandwidth usage database. .